One of the major design issues in wireless overlay networks is the support of vertical handoff. It is becoming essential to offer vertical handoff solutions where users can move among various network types efficiently and seamlessly. Vertical handoff is the switching process between heterogeneous wireless networks. In this paper, we propose and analyze a novel vertical handoff decision strategy that considers the performance of the whole system. This strategy takes into account the network bandwidth, received signal strength (RSS) and variation of RSS. The performance comparison of the proposed vertical handoff decision scheme and existing scheme shows that the proposed scheme can reduce the handoff call dropping probability. Keywords-wireless overlay networks, vertical handoffI.
The measurement of alternating current (AC) is realized by using fiber Bragg grating (FBG), giant magnetostriction material (GMM), and the technology of fiber coupler demodulation (fiber wavelength division multiplexing filter, FWDMF). The magnetostrictive effect of GMM, the theoretical analysis of the FBG current measurement and the interrogation technology of FWDMF are introduced as well. The sensing unit of AC current measurement is constructed with magnetostrictive material and FBG. The feasibility of AC current measurement by using this method is proved, when the AC exciting current is in the scope of 0~2A. INTRODUCTIONWith the development of optic sensor technology, small in size, low loss, high sensitivity and electric insulation, such characteristics make these sensors become one of the most promising sensors. Based on fiber Bragg grating (FBG) good performances of wavelength modulation, high resolution, anti-electromagnetic interference, small size, reproducible[1], easy to pose a distributed architecture and able to realize mass production, some experts and scholars tried to take advantage of FBG sensor technique to produce fiber current sensor and have achieved certain results.The thermal effect modulation for fiber current sensor was implemented by using the attached metal (aluminum or copper) film or metal sets around the fiber grating by Cavaleiro [2] and Jia [3]. The force effect modulation for fiber current sensor was proposed using the FBG particular structure with electromagnetic force drive by Gong [4][5][6][7].The specific FBG current sensor structures also have been reported based on the reverse piezoelectric effect of piezoelectric material [8-9], the magnetostrictive effect of magnetostrictive alloys [10] and giant-magnetostrictive materials(GMM) [11][12][13][14],but there are still some problems, such as the impact of ambient temperature can not be overcome [2], the complex structural [4], the smaller range [5 ], just DC current measurement was achieved [7,11,12], and even AC current measurement can be measured but the demodulation system is complex [14].FBG current sensing was researched by FBG intelligent structure with new materials and structure in this paper. Solenoid can produce magnetic fields by current incentive, the strain of giant magnetostrictive material produces, and the center wavelength of the FBG adhesive on its surface will shift, thus current will be demodulated by the technology of fiber coupler demodulation (fiber wavelength division multiplexing filter, FWDMF).. THE PRINCIPLE OF FBG CURRENT SENSOR The magnetostrictive effect of Giant magnetostrictive materialsGiant magnetostrictive materials (GMM) have been paid on high attention in the industry, which is widely used in magnetic electro-mechanical transducers, sonar systems and the sensors.The strain of GMM can be expressed at the lower incentive magnetic intensity and low incentive frequency [15] *
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.